As known, motor vehicles have a front frame accommodated in the front engine compartment and designed so as to obtain an adequate degree of safety, in particular for the passengers in the passenger compartment, in the event of accidents with front impact.
In particular, the front frame is provided with at least two pairs of longitudinal struts, having collapsible zones to absorb energy due to impacts at relatively high speed. In the event of front impact against an obstacle arranged approximately at the centreline of the motor vehicle, the known solutions allow an excellent degree of safety to be obtained in the passenger compartment. Nevertheless, the results are not as satisfactory when the front impact occurs with an offset, that is with a deviation with respect to the longitudinal centreline axis, and concerns only a front edge of the motor vehicle. Regulations in particular provide safety tests with impacts where there is a so-called “small overlap” (for example equal to 25%) between the motor vehicle and the obstacle during the impact. In these cases, the stresses due to the impact are only unloaded onto one side of the motor vehicle and therefore, only onto certain longitudinal struts of the motor vehicle. Since the plastic deformation of the front frame is not able to absorb all the impact energy, the passenger compartment is also subject to deformations which instead should be avoided to ensure the safety of the passengers.
It is known from Patent Application DE102012013277A1, to provide a structure which, by moving during the impact, pushes the powertrain unit in transversal direction, towards the side opposite to the one which is concerned by the impact, so as to exploit the inertia of the powertrain unit to cause the motor vehicle to move away from the obstacle. This deviation in sideways direction of the whole motor vehicle is extremely advantageous for substantially keeping intact the part of body defining the passenger compartment.
The need is felt to improve the solutions shown diagrammatically in DE102012013277A1, so as to obtain an embodiment which can be applied to front frames of known type by means of a limited number of modifications and which, at the same time, is effective.